a = 10
b = a
print(id(a))
print(id(b))
a = 2
print(id(a), a)
print(id(b))

import copy
a = [1, 2, 3]
b = copy.copy(a) # 浅拷贝，只拷贝第一层
print(id(a))
print(id(b))
a[0] = 100
print(id(a), a)